On Feb 22, 11:07*pm, Glenda Copeland gscopel...@Use-Author-Supplied-
Address.invalid wrote:
How do I adjust a thermostat so that the heat reaches the set temperature?

My Honeywell round thermostat has a bulb with mercury in it and a coil of
metal that seems to control when it makes electrical contact.

When I set the Honeywell bulb thermostat to 68°F, the heat only gets to
about 58°F. Likewise, when I set the thermostat to 85°F, the heat shuts off
when it reaches about 75°F.

This works fine except my husband keeps yelling at me for setting the
thermostat to 85°.

I know the simple answer is to change him but why do thermostats have
numbers on them if they're not even close to those numbers?

Is there a way to adjust the temperature? When I pull the round cover off,
I see a copper pointer on the bottom with etch marks on the plate below but
that pointer is already all the way to the left and moving it to the right
just seems to make the offset error worse.

What's the procedure to adjust a Honewell round thermostat to reach the set
point before turning off?

The problem you have is called hysteresis. When the temperature rises
the 'stat switches off & the temp. falls but the stat does not close
at the same temperature as when it was rising. The hysteresis should
only be a couple of degrees but now it's obviously a lot more. This is
due to ancient technology and probably wear and tear and lack of
lubrication. The mercury bulb is indestructable but the rest of the
'stat wears. Get a new themostat. It will pay for itself in a year.
http://en.wikipedia.org/wiki/Hysteresis